1. Field of the Invention
The invention relates to a microscope which emits a light for measurement, e.g. infrared light, ultraviolet light, visible light, etc., to a microscopic analysis position of a surface of a macroscopic sample.
2. Description of Related Art
An infrared microscope is used for examining a molecular structure based on a functional group of an organic compound attached to a solid surface (of a sample), for example. Specifically, an infrared light, which is condensed to a small diameter, is emitted to a particular microscopic part (e.g. an analysis position of 15 μm×15 μm) of the sample surface. Because the microscopic part of the sample surface generates a particular spectrum of the molecular structure based on the functional group of the organic compound, the spectrum is detected and analyzed for identification and quantification of the organic compound (see Patent Reference 1, for example).
The aforementioned infrared microscope includes an image acquisition section, e.g. CCD camera, CMOS camera, etc., for the analyst to observe the sample surface. By using the image acquisition section, an optical image of the sample surface can be observed to determine the analysis position of the sample surface. For example, a light source, e.g. a halogen lamp, is used to emit a visible light to an position of the sample surface that includes the analysis position and a visible light reflected from the area including the analysis position is detected by the CCD camera to form the optical image, which is shown as an optical image picture, for the analyst to observe and designate where the infrared light is to be emitted on the sample and where an analysis range is on the sample.
FIG. 6 is a structural diagram illustrating main components of a conventional infrared microscope, wherein a direction that is level with the ground is defined as an X direction, a direction perpendicular to the X direction that is level with the ground is defined as a Y direction, and a direction perpendicular to the X direction and the Y direction is defined as a Z direction. An infrared microscope 101 includes a sample stage 10 (sample disposing mechanism) carrying a sample S, an infrared light source section 20 for emitting an infrared light, a visible light source section 30 for emitting a visible light, a detection section 240 for detecting the infrared light, an image acquisition section 50 having a detection surface for detecting the visible light, Cassegrain lenses 260 and 261 (optical elements), a plate-shaped exchange lens 70, and a computer 190 for controlling the whole infrared microscope 101.
The sample stage 10 includes a micro-movement stage (sample platen) which is movable, an X direction driving mechanism (not shown), a Y direction driving mechanism (not shown), and a Z direction driving mechanism (not shown). The sample S may be disposed on or removed from the top of the micro-movement stage. A sample stage controlling section 191a of the computer 190 outputs a necessary driving signal to the aforementioned driving mechanisms to move the micro-movement stage to the X direction, Y direction, and Z direction as desired.
The infrared light source section 20 is a Fourier transform infrared spectrophotometer for emitting the infrared light having an intensity that varies with time (interferogram). In addition, the infrared light source section 20 is disposed in a way that the emitted infrared light is condensed by the Cassegrain lenses 260 and 261 and emitted to the analysis position (e.g. 15 μm×15 μm) of the sample S on the sample stage 10 after being reflected by a mirror 21, an exchange mirror 22, a penetration/reflection exchange mirror 23, concave lenses 24 and 25, and translucent lenses 26 and 27. The detection section 240 includes a detector 241, a condenser lens 242, and a mirror 243. The condenser lens 242 and the mirror 243 are disposed before the detector 241.
The visible light source section 30 is used to emit the visible light. Moreover, the visible light source section 30 is disposed in a way that the emitted visible light is condensed by the Cassegrain lenses 260 and 261 and emitted to the area that includes the analysis position of the surface of the sample S carried on the sample stage 10 after penetrating through and being reflected by a lens 31, the exchange mirror 22, the penetration/reflection exchange mirror 23, the concave lenses 24 and 25, and the translucent lenses 26 and 27. The image acquisition section 50 includes a CCD camera 51 having the detection surface for detecting the visible light and a relay lens 52 disposed before the CCD camera 51.
In order for the image acquisition section 50 to acquire the optical image of the area that includes the analysis position of the surface of the sample S by the same optical axis (light path) that an optical system guides the infrared light to the detection section 240, an exchange lens 270 is disposed on the light path (in a −Z direction) above the sample stage 10, along which the infrared light is guided to the detection section 240, and the exchange lens 270 may be moved to a position that intersects the light path or be moved away from the light path. Accordingly, the infrared light from the analysis position of the sample S is condensed by the Cassegrain lens 260 and transmitted in the predetermined direction (−Z direction), and after being reflected to a −X direction by the exchange lens 270 on the light path, the infrared light is detected by the detection section 240. Additionally, the visible light from the area that includes the analysis position of the surface of the sample S is condensed by the Cassegrain lens 260 and transmitted in the predetermined direction (−Z direction) to be detected by the detection surface of the CCD camera 51.
The computer 190 includes a CPU 191 (control section) and is connected with a monitor 93 (display device) and an operation section 92 (input device). Referring to the block diagram that illustrates the functions performed by the CPU 191, the CPU 191 includes a sample stage control section 191a for controlling the sample stage 10, an image acquisition control section 191b for acquiring the optical image from the image acquisition section 50 and displaying the optical image picture (measurement picture) on the monitor 93, and an analysis control section 191c for performing a Fourier transform and calculating an infrared spectrum by obtaining infrared light information of the analysis position of the sample S from the detection section 240.
FIG. 7 illustrates an example of the picture displayed by the monitor of the infrared microscope 101. The measurement picture (e.g. 500 μm×400 μm) obtained from the image acquisition section 50 is displayed by the monitor 93. A dotted-line quadrilateral analysis position picture is shown in the measurement picture to indicate the analysis position (e.g. 50 μm×50 μm) in the current position relationship of the micro-movement stage.
The sample stage control section 191a is used for controlling the micro-movement stage to move in the X direction, the Y direction, and the Z direction according to a signal from the operation section 92. For instance, the analyst observes the measurement picture displayed by the monitor 93 and at the same time uses the operation section 92 to perform operations, such as dragging by mouse or scroll bar, on the measurement picture, so as to designate the position (analysis position) of the sample S, to which the infrared light is emitted. Accordingly, the sample stage control section 191a moves the micro-movement stage in the X direction, the Y direction, and the Z direction, such that the infrared light is emitted to the designated position. In addition, if the position is not desirable, the analyst may repeat the operation to correct the position, check the position of the analysis position picture on the measurement picture, and then begin the measurement. In other words, the analyst produces a picture of the area including the analysis position of the surface of the sample S by the CCD camera 51 and determines the desired analysis position based on the measurement picture. Alternatively, the analyst may visually inspect at which side of the sample S the optical axis of the measurement optical system is located to approximately align the position. Furthermore, if the position is not desirable, the analyst repeats the operation to correct the position by visual inspection, check the position of the analysis position picture on the measurement picture, and then begin the measurement.